Document Type : Original Research Paper
Authors
1 Department of Mining Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran, Iran
2 Department of mining engineering, Faculty of engineering, Tarbiat Modares University, Tehran, Iran
Abstract
This work aims to investigate the effect of water saturation on cutting forces and chipping efficiency by performing a series of small-scale linear cutting tests with a chisel pick on twelve low- and medium-strength rock samples. The peak and mean cutting force acting on the chisel pick are measured and recorded under dry and saturated cutting conditions by the strain sensors that are embedded in the dynamometer. Also the amplitude of cutting force fluctuations in dry and saturated cutting conditions is compared by the standard deviation measurement of cutting force data, and its relationship with the size of cutting fragments is investigated. The results obtained show that the peak cutting force is reduced in saturated conditions compared to dry conditions. The mean cutting force in the synthetic sample cutting test is unchanged or in some cases increase, while in the natural samples it decreases. The relative increase in the mean cutting force in synthetic rock specimens is due to the paste state of fine materials produced from saturated cutting and chisel pick clogging. A strong correlation is found between the standard deviation of cutting force data and the average size of rock debris, indicating that the standard deviation of cutting force data is a useful measure for evaluating the chipping efficiency. The present study's findings reveal that to have an efficient excavation system in field operations, it is necessary to consider the presence of water and saturated conditions in designing the cutting machine's operating parameters and predicting the performance of mechanical excavators.
Keywords
[1]. Bilgin, N., Copur, H., and Balci, C. (2013). Mechanical Excavation in Mining and Civil Industries, Taylor & Francis, 388 P.
[2]. Balci, C. and Bilgin, N. (2007). Correlative study of linear small and full-scale rock cutting tests to select mechanized excavation machines. International Journal of Rock Mechanics and Mining Sciences. 44 (3): 468-476.
[3]. Bilgin, N. (1977). Investigations into the mechanical cutting characteristics of some medium and high strength rocks. PhD University of Newcastle upon Tyne.
[4]. Ouyang, Y., Chen, X., Yang, Q., Xu, Y., and Qiu, Y. (2021). Experimental Study on Sandstone Rock Cutting with Chisel Picks. Rock Mechanics and Rock Engineering. 54 (3): 1609-1619.
[5]. Yilmaz, N.G., Yurdakul, M. and Goktan, R.M. (2007). Prediction of radial bit cutting force in high-strength rocks using multiple linear regression analysis. International Journal of Rock Mechanics and Mining Sciences. 44 (6): 962-970.
[6]. Bilgin, N., Demircin, M., Copur, H., Balci, C., Tuncdemir, H., and Akcin, N. (2006). Dominant rock properties affecting the performance of conical picks and the comparison of some experimental and theoretical results. International Journal of Rock Mechanics and Mining Sciences. 43 (1): 139-156.
[7]. Tiryaki, B., Boland, J., and Li, X. (2010). Empirical models to predict mean cutting forces on point-attack pick cutters. International Journal of Rock Mechanics and Mining Sciences. 47 (5): 858-864.
[8]. Comakli, R., Kahraman, S., and Balci, C. (2014). Performance prediction of roadheaders in metallic ore excavation. Tunnelling and Underground Space Technology. 40 (38-45.
[9]. Goktan, R.M. (1995). Prediction of drag bit cutting force in hard rocks, proc, 3rd international symposium on mine mechanization and automation, Golden, Colorado, 10-31.
[10]. Copur, H., Tuncdemir, H., Bilgin, N., and Dincer, T. (2001). Specific energy as a criterion for the use of rapid excavation systems in Turkish mines. Mining Technology. 110 (3): 149-157.
[11]. Copur, H., Balci, C. and Tumac, D. (2011). Field and laboratory studies on natural stones leading to empirical performance prediction of chain saw machines. International Journal of Rock Mechanics and Mining Sciences. 48 (2): 269-282.
[12]. Copur, H. (2010). Linear stone cutting tests with chisel tools for identification of cutting principles and predicting performance of chain saw machines. International Journal of Rock Mechanics and Mining Sciences. 47 (1): 104-120.
[13]. Shao, W., Li, X., Sun, Y., and Huang, H. (2017). Parametric study of rock cutting with SMART∗ CUT picks. Tunnelling and Underground Space Technology. 61: 134-144.
[14]. Wang, X., Su, O., Wang, Q.F., and Liang, Y.P. (2017). Effect of cutting depth and line spacing on the cuttability behavior of sandstones by conical picks. Arabian Journal of Geosciences. 10 (23): 1-13.
[15]. Abu Bakar, M.Z. and Gertsch, L.S. (2013). Evaluation of saturation effects on drag pick cutting of a brittle sandstone from full scale linear cutting tests. Tunnelling and Underground Space Technology. 34: 124-134.
[16]. McFeat-Smith, I. and Fowell, R. J. (1977). Correlation of rock properties and the cutting performance of tunnelling machines, proc, Conference on Rock Engineering, The University of Newcastle upon Tyne, 581-602.
[17]. Wang, X., Liang, Y., Wang, Q., and Zhang, Z. (2017). Empirical models for tool forces prediction of drag-typed picks based on principal component regression and ridge regression methods. Tunnelling and Underground Space Technology. 62: 75-95.
[18]. Dogruoz, C. and Bolukbasi, N. (2014). Effect of cutting tool blunting on the performances of various mechanical excavators used in low-and medium-strength rocks. Bulletin of Engineering Geology and the Environment. 73 (3): 781-789.
[19]. Balci, C., Demircin, M., Copur, H., and Tuncdemir, H. (2004). Estimation of optimum specific energy based on rock properties for assessment of roadheader performance. Journal of the Southern African Institute of Mining and Metallurgy. 104 (11): 633-642.
[20]. Tiryaki, B. and Dikmen, A.C. (2006). Effects of rock properties on specific cutting energy in linear cutting of sandstones by picks. Rock mechanics and rock engineering. 39 (2): 89-120.
[21]. Copur, H., Bilgin, N., Balci, C., Tumac, D. and Avunduk, E. (2017). Effects of different cutting patterns and experimental conditions on the performance of a conical drag tool. Rock Mechanics and Rock Engineering. 50 (6): 1585-1609.
[22]. Tumac, D., Copur, H., Balci, C., Er, S., and Avunduk, E. (2018). Investigation into the Effects of Textural Properties on Cuttability Performance of a Chisel Tool. Rock Mechanics and Rock Engineering. 51 (4): 1227-1248.
[23]. Rostami, K., Khademi Hamidi, J., and Nejati, H.R. (2020). Use of rock microscale properties for introducing a cuttability index in rock cutting with a chisel pick. Arabian Journal of Geosciences. 13 (18): 1-12.
[24]. Rojek, J., Labra, C., Su, O., and Oñate, E. (2012). Comparative study of different discrete element models and evaluation of equivalent micromechanical parameters. International Journal of Solids and Structures. 49 (13): 1497-1517.
[25]. Bejari, H. and Khademi Hamidi, J. (2013). Simultaneous effects of joint spacing and orientation on TBM cutting efficiency in jointed rock masses. Rock mechanics and rock engineering. 46 (4): 897-907.
[26]. Carbonell, J.M., Oñate, E., and Suárez, B. (2013). Modelling of tunnelling processes and rock cutting tool wear with the particle finite element method. Computational Mechanics. 52 (3): 607-629.
[27]. Liu, S., Liu, Z., Cui, X., and Jiang, H. (2014). Rock breaking of conical cutter with assistance of front and rear water jet. Tunnelling and Underground Space Technology. 42: 78-86.
[28]. Menezes, P.L., Lovell, M. R., Avdeev, I.V., and Higgs, C.F. (2014). Studies on the formation of discontinuous rock fragments during cutting operation. International Journal of Rock Mechanics and Mining Sciences. 71: 131-142.
[29]. Xuefeng, L., Shibo, W., Shirong, G., Malekian, R., and Zhixiong, L. (2018). Investigation on the influence mechanism of rock brittleness on rock fragmentation and cutting performance by discrete element method. Measurement. 113: 120-130.
[30]. Li, X., Wang, S., Ge, S., Malekian, R., Li, Z., and Li, Y. (2018). A study on drum cutting properties with full-scale experiments and numerical simulations. Measurement. 114: 25-36.
[31]. Cai, X., Zhou, Z., Liu, K., Du, X., and Zang, H. (2019). Water-weakening effects on the mechanical behavior of different rock types: phenomena and mechanisms. Applied Sciences. 9 (20): 4450.
[32]. Hawkins, A. and McConnell, B. (1992). Sensitivity of sandstone strength and deformability to changes in moisture content. Quarterly Journal of Engineering Geology and Hydrogeology. 25 (2): 115-130.
[33]. Tang, S. (2018). The effects of water on the strength of black sandstone in a brittle regime. Engineering Geology. 239: 167-178.
[34]. Yilmaz, I. (2010). Influence of water content on the strength and deformability of gypsum. International Journal of Rock Mechanics and Mining Sciences. 47 (2): 342-347.
[35]. Colback, P. and Wiid, B. (1965). The influence of moisture content on the compressive strength of rocks. Geophysics.
[36]. Dyke, C. and Dobereiner, L. (1991). Evaluating the strength and deformability of sandstones, Geological Society of London.
[37]. Jiang, Q., Cui, J., Feng, X., and Jiang, Y. (2014). Application of computerized tomographic scanning to the study of water-induced weakening of mudstone. Bulletin of Engineering Geology and the Environment. 73 (4): 1293-1301.
[38]. Török, Á. and Vásárhelyi, B. (2010). The influence of fabric and water content on selected rock mechanical parameters of travertine, examples from Hungary. Engineering Geology. 115 (3-4): 237-245.
[39]. Zhou, Z., Cai, X., Cao, W., Li, X., and Xiong, C. (2016). Influence of water content on mechanical properties of rock in both saturation and drying processes. Rock Mechanics and Rock Engineering. 49 (8): 3009-3025.
[40]. Ojo, O. and Brook, N. (1990). The effect of moisture on some mechanical properties of rock. Mining Science and Technology. 10 (2): 145-156.
[41]. Lashkaripour, G.R. (2002). Predicting mechanical properties of mudrock from index parameters. Bulletin of Engineering Geology and the Environment. 61 (1): 73-77.
[42]. Vasarhelyi, B. and Ván, P. (2006). Influence of water content on the strength of rock. Engineering Geology. 84 (1-2): 70-74.
[43]. Karakul, H. and Ulusay, R. (2013). Empirical correlations for predicting strength properties of rocks from P-wave velocity under different degrees of saturation. Rock mechanics and rock engineering. 46 (5): 981-999.
[44]. Guha Roy, D., Singh, T., Kodikara, J., and Das, R. (2017). Effect of water saturation on the fracture and mechanical properties of sedimentary rocks. Rock Mechanics and Rock Engineering. 50 (10): 2585-2600.
[45]. Maruvanchery, V. and Kim, E. (2019). Effects of water on rock fracture properties: Studies of mode I fracture toughness, crack propagation velocity, and consumed energy in calcite-cemented sandstone. Geomechanics and Engineering. 17 (1): 57-67.
[46]. Erguler, Z. and Ulusay, R. (2009). Water-induced variations in mechanical properties of clay-bearing rocks. International Journal of Rock Mechanics and Mining Sciences. 46 (2): 355-370.
[47]. Hashiba, K. and Fukui, K. (2015). Effect of water on the deformation and failure of rock in uniaxial tension. Rock Mechanics and Rock Engineering. 48 (5): 1751-1761.
[48]. Wong, L.N.Y. and Jong, M.C. (2014). Water saturation effects on the Brazilian tensile strength of gypsum and assessment of cracking processes using high-speed video. Rock Mechanics and Rock Engineering. 47 (4): 1103-1115.
[49]. Kwasniewski, M. and Rodriguez-Oitaben, P. (2009). Effect of water on the deformability of rocks under uniaxial compression, proc, ISRM Regional Symposium-EUROCK 2009.
[50]. Mann, R.L. and Fatt, I. (1960). Effect of pore fluids on the elastic properties of sandstone. Geophysics. 25 (2): 433-444.
[51]. Shakoor, A. and Barefield, E.H. (2009). Relationship between unconfined compressive strength and degree of saturation for selected sandstones. Environmental and Engineering Geoscience. 15 (1): 29-40.
[52]. Burshtein, L. (1969). Effect of moisture on the strength and deformability of sandstone. Soviet mining science. 5 (5): 573-576.
[53]. Pellet, F., Keshavarz, M., and Boulon, M. (2013). Influence of humidity conditions on shear strength of clay rock discontinuities. Engineering Geology. 157: 33-38.
[54]. Zhao, Z., Yang, J., Zhou, D., and Chen, Y. (2017). Experimental investigation on the wetting-induced weakening of sandstone joints. Engineering Geology. 225: 61-67.
[55]. Tang, Z.C., Zhang, Q.Z., Peng, J., and Jiao, Y.Y. (2019). Experimental study on the water-weakening shear behaviors of sandstone joints collected from the middle region of Yunnan province, PR China. Engineering Geology. 258: 105-161.
[56]. Roxborough, F. and Rispin, A. (1973). Mechanical cutting characteristics of lower chalk. Tunnels & Tunnelling International. 5 (3).
[57]. Oreilly, M.P., Hignett, H.J., Tough, S.G., Roxborough, F.F., and PIRRIE, N.D. (1979). Tunnelling trials in chalk. Proceedings of the Institution of Civil Engineers. 67 (2): 255-283.
[58]. Phillips, H.R. and Roxborough, F. F. (1981). The influence of tool material on the wear rate of rock cutting picks, proc, 34th Annual Conference of Australian Institute of Metals, Brisbane, 52-56.
[59]. Ford, L.M. and Friedman, M. (1983). Optimization of rock-cutting tools used in coal mining, proc, The 24th US Symposium on Rock Mechanics (USRMS), Texas, 725-732.
[60]. Mammen, J., Saydam, S., and Hagan, P. (2009). A study on the effect of moisture content on rock cutting performance, proc, Coal Operators Conference, 340-347.
[61]. Abu Bakar, M. and Gertsch, L. (2011). Saturation effects on disc cutting of sandstone, proc, 45th US Rock Mechanics/Geomechanics Symposium.
[62]. Abu Bakar, M., Gertsch, L.S., and Rostami, J. (2014). Evaluation of fragments from disc cutting of dry and saturated sandstone. Rock mechanics and rock engineering. 47 (5): 1891-1903.
[63]. Rosin, P. and Rammler, E. (1933). Laws governing the fineness of powdered coal. Journal of Institute of Fuel. 7: 29-36.
[64]. Ulusay, R. and Hudson, J. (2007). The complete ISRM suggested methods for rock characterization, testing and monitoring. ISRM Turkish National Group, Ankara, Turkey.
[65]. D2938-95, A. (1995). Standard test method for unconfined compressive strength of intact rock core specimens, Annual Book of ASTM Standards, American Society for Testing and Materials, West Conshohocken.
[66]. D3967-95, A. (1995). Standard test method for splitting tensile strength of intact rock core specimens, Annual Book of ASTM Standards, American Society for Testing and Materials, West Conshohocken.
[67]. D4543-08, A. (2008). Standard practices for preparing rock core as cylindrical test specimens and verifying conformance to dimensional and shape tolerances, Annual Book of ASTM Standards, American Society for Testing and Materials, West Conshohocken.
[68]. Bieniawski, Z.T. (1989). Engineering rock mass classifications: a complete manual for engineers and geologists in mining, civil, and petroleum engineering, John Wiley & Sons.
[69]. Barker, J. (1964). A laboratory investigation of rock cutting using large picks, proc, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 519-534.
[70]. Roxborough, F.F. (1973). Cutting rock with picks. The mining engineer. 132 (153): 445-454.
[71]. Jackson, E., Devaux, M. and Machin, J. (2007). Performance prediction for a subsea mechanical trenching wheel, proc, Offshore Site Investigation and Geotechnics: Confronting New Challenges and Sharing Knowledge.
[72]. Yasar, S. and Yilmaz, A.O. (2017). A novel mobile testing equipment for rock cuttability assessment: vertical rock cutting rig (VRCR). Rock Mechanics and Rock Engineering. 50 (4): 857-869.
[73] Yasar, S. and Yilmaz, A. O. (2019). Vertical rock cutting rig (VRCR) suggested for performance prediction of roadheaders. International Journal of Mining, Reclamation and Environment. 33 (3): 149-168.
[74] Yasar, S. and Yilmaz, A. O. (2017). Rock cutting tests with a simple-shaped chisel pick to provide some useful data. Rock Mechanics and Rock Engineering. 50 (12): 3261-3269.
[75] Potts, E. and Shuttleworth, P. (1958). A study of ploughability of coal with special reference to the effects of blade shape, direction of planning to the cleat, planning speed and influence of water infusion. Transactions of the Institution of Mining Engineers. 117: 519-553.
[76] Evans, I. (1958). Theoretical aspects of coal ploughing. Mechanical properties of non-metallic brittle materials. 451-468.
[77] Evans, I. (1962). A theory of the basic mechanics of coal ploughing, proc, International Symposium on Mining Research, University of Missouri, 761-798.
[78] Evans, I. and Pomeroy, C. (1966). The strength, fracture and workability of coal, Pergamon Press, Oxford, P.
[79] Allington, A. V. (1969). The machining of rock materials. Newcastle University.
[80] Nishimatsu, Y. (1972). The mechanics of rock cutting. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. 9 (2): 261-270.
[81] Rostamsowlat, I., Akbari, B., and Evans, B. (2018). Analysis of rock cutting process with a blunt PDC cutter under different wear flat inclination angles. Journal of Petroleum Science and Engineering. 171: 771-783.
[82] Rostamsowlat, I., Richard, T., and Evans, B. (2018). An experimental study of the effect of back rake angle in rock cutting. International Journal of Rock Mechanics and Mining Sciences. 107: 224-232.
[83] Mohammadi, M., Khademi Hamidi, J., Rostami, J., and Goshtasbi, K. (2020). A closer look into chip shape/size and efficiency of rock cutting with a simple chisel pick: a laboratory scale investigation. Rock Mechanics and Rock Engineering. 53 (3): 1375-1392.
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